Conventionally, with a view to preventing a shock that will result from a torque interruption occurring during a gear change based on a transmission in which gear change operations of a manual transmission with a high transmission efficiency are automated, there have been proposed vehicle driving systems for hybrid vehicles which include a twin-clutch type transmission in which two input shafts each have a gear group and can individually be connected to an engine via a corresponding clutch, and one of the input shafts can be driven by a motor generator (refer to Patent Literature 1).
In a vehicle driving system 200 of Patent Literature 1, as shown in FIG. 19, two input shafts 201, 202 are connected individually to an engine Eng via clutches C1, C2, and further, a motor generator MG is connected to the input shaft 202. In addition, by engaging a dog clutch 205, the input shaft 202 is connected to a countershaft 207 via a low-speed side gear train 206, and the input shaft 201 is connected to the countershaft 207 via a high-speed side gear train 209 by engaging a dog clutch 208.
It is disclosed that the motor generator MG is driven by a driving force from the countershaft 207 so as to generate electricity through regeneration, and when the clutch C2 is engaged, the motor generator MG is driven by the engine Eng to thereby generate electricity.